The end shape of tungsten electrode has an influence on the stability of arc. If the end face is uneven, the generated arc is neither concentrated nor stable. Therefore, the tungsten tip must be polished. When welding thin plate and welding current is small, small diameter tungsten electrode can be used, and its end can be ground into a sharp cone angle, which makes the arc easy to ignite and stabilize. However, when the welding current is large, the end will overheat and melt, which will increase the burning loss, and the arc spot will also spread to the conical surface of the tungsten end, which will make the arc column obviously unstable and affect the weld formation. When welding with high current, the end of tungsten electrode is required to be ground into a cone with blunt cone angle or flat top, which can stabilize the arc spot, reduce the diffusion of arc column, concentrate the heat at the welding position and form a uniform weld. Small diameter, small cone angle and small top diameter should be selected as far as possible when welding thin plates with low current, which is beneficial to arc striking and stable work. When the current increases, the cone angle should increase with the increase of tungsten electrode diameter, and the flat top diameter should also increase to control the end current and avoid abnormal burning loss. At the same time, the grinding of flat top diameter is beneficial to prevent the arc column from spreading due to spot climbing. This arc column diffusion caused by too small flat top diameter and spot climbing will lead to uneven current density in the arc and temperature distribution in the molten pool, thus aggravating convection caused by electromagnetic force in the molten pool. The weld penetration decreases and the weld width increases.